Work-rest blade for centerless grinders



July 16, 1929. H. SKALL WORK REST BLADE FOR CENTERLESS GRINDERS Filed Feb. 1928 Patented July 16, 1929.

UNITED STATES PATENT OFFICE.

SPECIALTIES,

IN (1., OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

WORK-REST BLADE FOR CENTERLESS GRINDERS.

Application filed February 6, 1928. Serial No. 252,169.

This invention relates more particularly to the type of centerless grinders in which the grinding operation is performed by the perimeter of the grinding wheel and the present improvement has for its object:

To provide a structural formation of a work support or blade for centerless grinders of the type above mentioned, embodying the feature of a maximum durability,- efliciency and economy in production, all as will hereinafter more fully appear.

In the accompanying drawing ,Fig. 1 is an end elevation, partly in section, embodying a mechanical arrangement and structural formation of the invention. Fig. 2 is a side elevation of the preferred form of the work supporting blade.

Like referencenumerals indicate like parts in both views. As shown in Fig. 1 of the drawing, the

. centerless grinder mechanism comprises in the main, a' downwardly and rapidly rotating grinding wheel 1, and an upwardly and slowly rotating feeder or regulating wheel 2, with the movement of the peripheries of the two wheels in opposite directions where they contact with the work, adapted to im part a turning movement to such work during the grinding operation. The work being supported in proper position by the usual work rest or blade 3, carried in an ad-.

justable manner is a fixedsupporting post 4, with the top face of the blade 3 in proper operative relation to a line drawn between the centers of the wheels 1 and 2 aforesaid. Previous to this invention work supports or blades of the type above described, were formed with a main body portion of cheaper metal with the work supporting face of the blade formed of a strip of steel alloy, welded to said main body portion and having the required degree of wear resisting hardness. Such form of work supporting blade was subject to considerable wear in continued use and was open to the farther serious ohjection that particles of the metallic article operated on and of the grinding wheel, released in actual use, had a tendency to adhere to and hill upon the top surface of a blade of thepresent type, I have found after extended experiments, changes and practical tests during such experiments, that cast iron, preferably in the form of an iron alloy hereinafter described, will when its work supporting surface is chilled to a moderate depth, provide in a ready and economical manner, a work support or blade having a much greater life than the much more expensive work supports heretofore used and referred to above, and with an almost entire absence of an accumulation or billing of the ground particles on its supporting face, above referred to, as an objectionable feature in the former type of work supports.

The principal alloying elements in the present iron alloy, above referred to, are manganese, silicon and carbon, with a small percentage of phosphorus, sulphur and combined carbon and chromium. The proportions of which may be slightly varied within limits given in the following table and by which superior results are obtained:

The remainder iron.

Work rests or supporting blades made from alloyed iron containing materials in the proportions specified in the above table, and after the resting or supporting face 3' of the support or blade 3 formed therefrom has been chilled in an ordinary manner to a depth approximately three-quarters of an inch, and a hardness of at least 50'Rockwell C numerals, possesses in a superior degree the desired wear resisting qualities and hardness above set forth.

Having fully described my invention, some depth with a hardness of at least 50 what I claim and desire to secure by Let- Rockwell G numerals and a chill face of a 1 ters Patent, is natural smooth and dense nature adapted to A- wear resisting work supporting blade resist deposit and piling up of grindings in 5 for centerless grinders,- comprising a cast actual use. metal alloy of iron, carbon, silicon, manga- In testimony whereof I hereunto aflix my nese, phosphorus, and chromium, the supsignature. porting face of-the blade having a chill of HAROLD SKALL. 

